Filter module and filter device

ABSTRACT

A filter module includes an axially extending central channel, a first hollow adapter having an interior through which the central channel extends, a second hollow adapter having an interior through which the central extends, one or more filter cells positioned between the first and second adapters and around the central channel, and an enclosure. The enclosure has a first retainer ring mounted around the first adapter, a second retainer ring mounted around the second adapter, and an envelope which is sealed to the first and second retainer rings and extends around the one or more filter cells.

This application is a continuation of U.S. patent application Ser. No.10/469,852, which is the United States National Phase of InternationalApplication No. PCT/EP02/01892, which was filed on Feb. 22, 2002, andclaimed priority of German Application No. 101 11 064.2, filed on Mar.8, 2001, all of which are incorporated by reference.

DESCRIPTION

The invention concerns a module for filtering media. The invention alsorelates to a filter device with a filter housing in which the filtermodule or the filter modules is/are installed together with aninstallation set.

The term filter cells is understood to include all structural types offilter cells, wherein the porous, planar components that can support aflow of a medium are preferably filter layers made of known basicmaterials, i.e., essentially, cellulose and/or artificial fibers andalso diatomite.

Filter devices essentially consist of a reusable filter housing and theassociated attachments for filtrate and nonfiltrate material, as well asexchangeable filters, such as filter modules with filter cartridges orfilter cells. For conventional filter devices, contact betweennonfiltrate material/filtrate and housing is unavoidable, so that thefilter housing must be cleaned after use, i.e., after the removal of theused filter. Here, cross contamination from charge to charge cannot beexcluded.

Another disadvantage is that contact of the operating personnel withcontaminated filter cartridges or filter modules, as well as housingparts, is unavoidable, which is extremely problematic, particularly fortoxic or infectious contaminants of the used filter module or fordangerous gaseous materials in the nonfiltrate material chamber.

The parts of the filter housing in contact with the product must beresistant to the nonfiltrate material/filtrate, which in turn makesvarious housing variants necessary. It is associated with thisdisadvantage that the filter housing cannot be standardized andadaptation to the appropriate medium is required.

In special application cases, the filter modules must be flushed andsterilized before use. In addition, a drip-free removal of the filtermodule from the filter housing is just as unlikely as complete residualfiltration, which represents a significant disadvantage, particularlyfor expensive media.

Attempts have already been made to solve these problems by enclosing thefilter cartridges or filter modules, but not all of the problems couldbe solved.

For example, DE 35 20 139 C2 describes a filter device for gases orfluids with a filter cartridge, which is attached to an adapter with twoopenings for the filtrate and nonfiltrate material. A media-sealedsleeve in the form of a tube is attached to this adapter. This sleevesurrounds the filter cartridge and during filtration contacts the wallsof the filter bowl.

However, when the filter is changed, fluid can flow from the spacebetween the supply connection or the outlet connection and thedownstream blocking element outwards and onto the cover. This makesadditional cleaning work necessary.

A corresponding enclosure of several filter cartridges is explained inDE 38 07 828 C2.

In a refinement of the filter-cartridge enclosure, which is described inDE 38 08 602 C2, the housing and also the supply and dischargeconnections are modified to prevent these disadvantages. The greatestdisadvantage of this device is that when a filtering bag is provided,adaptations to the housing and attachments must also always be provided,so that the so-called standard housing can no longer be used.Retrofitting filter cartridges with filter bags is thus not possible. Inaddition, increasing amounts of fluid are left behind in theintermediate space between the filtrate and nonfiltrate material. Thisremaining fluid must be discarded. Corrosive or toxic media hinder thedisposal of filter cartridges. This also applies for filter devicesbased on filter modules with filter cells.

In WO 98/23356, a filter device with a filter module is described. Itwas considered a disadvantage for conventional filter devices that afterthe removal of used filter modules, the housing had to be cleaned inorder to prevent contamination of subsequent fluids. In addition,residual fluid collects at the outlet of the housing, so that thehousing must be opened or removed, which is time- and cost-intensive.Therefore, it was proposed to completely enclose the filter modules,wherein a two-part compression-proof and pressure-sealed enclosurehousing is provided, which is removed and disposed of together with thefilter module. This enclosure housing is installed freely and without anadditional filter housing directly in the supply and discharge pipeline.Thus, the assembly and disassembly of this enclosure housing for thepurposes of disposal and for exchanging filter modules with enclosurehousings is complicated. Furthermore, residual fluid comes out of theopened connection of the enclosure housing and the supply and dischargepipelines, which is a big disadvantage for corrosive, expensive, andtoxic media. This enclosure housing requires a relatively large amountof space, so that either an adaptation of the filter housing or areduction of the filter modules must be performed. In addition, thispressure-sealed internal housing, which is used only one time, iscomplicated and expensive in terms of production. Another disadvantageof this so-called single-use housing is that these cannot be producedfor filter modules with filter surfaces >1 m².

Therefore, it is the task of the invention to create an enclosed filtermodule, and also a filter device which do not have the disadvantages ofknown filter modules and filter devices. In particular, residualfiltration should be possible at a lower cost for the production offilter modules. In addition, contamination of the housing should beessentially prevented and the invention should allow the use of standardmodules and standard housings.

This task is accomplished with a module that is characterized in thatthe enclosure device includes a media-sealed envelope and two retainingrings, the envelope is attached in a media-sealed fashion to theretaining rings, and each retaining ring is arranged on one adapter.

The envelope forms a so-called soft enclosure, which surrounds thefilter cell package and seals off the exterior in a media-sealedfashion. The provision of retaining rings enables a simple attachment ofthe envelope without the adapters having to be changed. Overall, theenclosure device requires no additional space, so that nothing has to bechanged to the dimensions of the filter cells and the filter housing.Therefore, standard housings and standard modules can be used, whichmerely have to be provided with the envelope.

The envelope does protect the housing from contamination, but when thefilter module is removed, residue of the medium can still be dischargedfrom the inlet or outlet opening. In order to enable drip-free removal,at least one retaining ring in the inlet or outlet opening may have atleast one valve.

By means of the valve or valves in the retaining ring or rings, theinner space of the filter module, i.e., the space located between thefilter cells and the envelope and forming the so-called nonfiltratechamber or the filtrate chamber according to operation, can be filledand/or aerated with the medium, wherein the valves are designed suchthat they immediately switch to the closed position when the filtermodule is removed from the filter housing. This effectively preventsleakage of residue of the medium. The attachment of the valves in theretaining ring or rings enables simple production without damaging theenvelope.

The envelope preferably consists of a flexible and/or elastic material.According to the purpose of use, corresponding materials are used whichare resistant to toxic or corrosive media or are quite safe in terms offood. Preferably, a plastic material is used which belongs to the sameclass of plastics as the components of the filter module, i.e., thefilter cells, spacing rings, etc., so that no material separation has tobe performed for the disposal of used filter modules.

To produce the enclosure, preferably a tube film is used, which ispulled over the filter module perpendicular to the longitudinal axis,wherein the retaining rings are already arranged in the correct positionat the tube film. Then the open ends of the tube are sealed, preferablyfused, in a media-tight fashion.

Conventional filter modules have at the upper end a bowl-shaped adapterand at the lower end a plug adapter, which carries on its outer surfaceat least one sealing ring, particularly an O-ring. Filter modules withsuch adapters can be used, wherein according to the configuration of theadapter, the retaining rings have to be adapted. Thus, retrofitting ofexisting filter modules is possible.

If the enclosure has already been provided for the production of thefilter module, it is advantageous if both adapters are the same, becausethen the same retaining rings can be used at both module ends. Thisreduces the production costs.

Preferably, plug adapters are used which carry on their outer side atleast one sealing element, particularly a sealing ring, preferably anO-ring, because these known adapters already have attachment means forthe retaining ring. The retaining rings are preferably set and attachedto the adapter like a bayonet.

After filtration, residue of the medium can still be present in thefiltrate or nonfiltrate channel, which can drip out when the filtermodule is removed. To prevent this, valves sealing these channels arearranged at least in the lower adapter and in the lower retaining ring.The valves are preferably configured as plate valves.

In order to be able to install the filter modules according to theinvention in existing filter housings, an installation set is providedwhich has at least one annular base plate and one cover plate. Theannular base plate is configured such that it fills up the space betweenthe housing base and the filter module so much that the upper side ofthe base plate forms a contact surface for the envelope, wherein thebase plate has a filtrate or nonfiltrate channel which connects thefiltrate or nonfiltrate supply from the housing base to the opening atthe lower retaining ring. Furthermore, the base plate has a means forreceiving the lower adapter and the lower retaining ring of the filtermodule. The cover plate is configured so that it fills up the spacebetween the housing cover wall and the filter module so much that thelower side of the cover plate forms a contact surface for the envelope.Furthermore, the cover plate has a means for receiving the upper adapterand the upper retaining ring.

The means for receiving the lower adapter includes a receiver bushing,which is designed such that the receiver provided originally as anadapter receiver fits in the base wall of the filter housing.

The cover plate is preferably formed in two parts and has an annularhead plate and a distributor head inserted in the center in the headplate.

The distributor head can have several ventilation channels. Preferably,the distributor head has one ventilation channel for the filtratechannel and/or one ventilation channel for the nonfiltrate chamber,wherein this ventilation channel connects to the ventilation channellocated in the upper retaining ring. The ventilation channel for thefiltrate or nonfiltrate chamber is important during the first filling ofthe filtrate or nonfiltrate chamber. Furthermore, the distributor headcan have a control channel, which connects to the space located betweenthe envelope and the housing in order to be able to recognize a possibleloss of the sealing function in the envelope at an early time.

If two or more filter modules are to be arranged one above the other inthe filter housing, the filtrate or nonfiltrate chambers of the filtermodule must be connected to each other by the valves arranged in theretaining rings. Therefore, it is advantageous if an intermediate plate,which has an opening, is arranged between the filter modules. Theintermediate plate is configured such that the space between the filtermodules is filled up so much that the two end surfaces each form acontact surface for the envelope of the filter module. Furthermore, thisintermediate plate has at least one connection channel, which connectsthe valve openings of the valves located in the retaining rings of thetwo filter modules to each other.

The filter device according to the invention has a filter housing inwhich at least one filter module according to the invention is arrangedtogether with the installation set. The envelope of the filter module ormodules is dimensioned such that during the filtration operation itcontacts the housing wall of the filter housing and the adjacentcomponents of the installation set. These adjacent componentsessentially include the base plate, the cover plate, and if necessarythe intermediate plate. This guarantees that the envelope does not haveto be compression-proof, because the pressure force is received andsupported by the components of the installation set or the housing wall.

The control channel can also be used to simplify the filling or emptyingof the filter module or modules. For this purpose, the filter device canhave a pressure device connected to the control channel. After thecompletion of the filtration, the envelope can be compressed by applyingan overpressure so that residual amounts are pressed out of thenonfiltrate chamber. During filling, a low pressure can be applied sothat the envelope contacts the housing wall or the components of theinstallation set.

In the following, example embodiments are explained in more detail withreference to the figures.

Shown are:

FIG. 1, a vertical partial section of a filter device according to afirst embodiment,

FIG. 2, an enlarged representation of the upper region of the filterdevice shown in FIG. 1,

FIG. 3, an enlarged representation in the region of the receiver bushingof the filter device shown in FIG. 1, and

FIG. 4, a partial section through a filter device according to anotherembodiment, which features several filter modules.

In FIG. 1, a filter device 1 is shown in vertical partial section. Thefilter device 1 has a filter housing 2, which consists of a housingupper part 4 and a housing base 12. The housing upper part 4 in turnsconsists of a housing cover wall 8, at which a housing connection 6 isarranged in the center, i.e., in the region of the center axis of thefilter housing, and a housing shell 10 extending downwards to thehousing cover wall 8. The housing upper part 4 is formed pressure-sealedand compression-proof and connected to the housing base 12 with atensioning device that is not shown.

The housing base 12 has a filtrate connection 16 arranged in the center,i.e., in the center axis of the filter device, and an eccentricnonfiltrate supply 14. For reverse operation, the nonfiltrate materialis supplied through the connection 16, thus the nonfiltrate connection16, and discharged through the “supply 14,” i.e., the outlet 14. In thefollowing, the module according to the invention is described inconnection with the first method of operation.

In the filter housing 2, a filter module is installed with the aid of aninstallation set, which consists of several components and is describedlater. The filter module, in the simplified representation shown here,has three filter cells 22, with each filter cell consisting of twodisk-shaped filter layers 23, which are connected to each other at theoutside periphery. All filter layers 23 have a central opening. Theseopenings together form a filtrate channel 18. Spacing rings 29 arelocated between the filter cells 22.

At the upper and lower ends of the filtrate channel 18, an upper adapter24 and a lower adapter 26 attach to the filter cells 22. The twoadapters are identical in structure and each carry sealing rings 28 ontheir outer side. Up to the point that the two adapters are notidentical, the construction of this example filter module is known fromthe state of the art, so that more a detailed explanation is notnecessary.

At the upper and lower adapters 24, 26, there are retaining rings 32,34, which can be set on the projections typically present on adapters ofthe bayonet seal type. On these retaining rings 32, 34, a soft enclosurein the form of an envelope 30 is attached, which is fused to theretaining rings in the embodiment shown here (fuse seam 31). Thisenvelope 30, which can be, e.g., a film, surrounds the filter cells 22and is dimensioned so that on one side it contacts the inner side of thehousing shell 10 and on the other side it contacts the installation setcomponents 60, 110, and 120, which will be described in detail inconnection with FIGS. 2 and 3. Thus, a nonfiltrate chamber 19 is formedbetween the filter cells and the envelope 30.

Both the upper and also the lower retaining rings 32, 34 each feature atleast one valve 40, 48, which are shown enlarged in FIGS. 2 and 3.

The valve 40 acts as a ventilation valve for the nonfiltrate chamber 19and the lower valve 48 as a supply valve for the nonfiltrate materialinto the nonfiltrate chamber 19. The valves 40, 48 each have a valvecover 42, 50 with a valve tappet 44, 52. The valve covers 42, 50 areconnected to the corresponding retaining ring 32, 34 over a spring 46,54.

The valve cover 50 of the inlet valve 48 is arranged in the nonfiltratechamber 19 and seals the valve opening 38 when the filter module isremoved from the filter housing 2. In the installed state, the valvetappet 52 contacts a projection 80 (see FIG. 3), so that the inlet valve48 in the installed state is always located in the open position andthus the inflow of nonfiltrate material into the nonfiltrate chamber 19is not impaired.

The valve cover 42 is also found in the nonfiltrate chamber 19. In theinstalled state, the valve 48 is open, so that the air present while thenonfiltrate material flows into the nonfiltrate chamber 19 can escape tothe outside through the ventilation channel 128 a, b. As soon as thenonfiltrate chamber 19 is filled with nonfiltrate material, a valve,which is arranged on the outlet 130 but is not shown, can then beclosed.

Additional adapter valves 90, 100 are arranged in the two adapters 24and 26.

The upper adapter valve 90 (see FIG. 2) has a valve ring 92, which isinserted in the upper adapter 24 in a sealed fashion. The valve ring 92has an annular valve opening 95, which can be sealed by a valve plate 94with valve tappet 96. The valve plate 94 projects into the filtratechannel 18 and then closes the valve opening 95 when the filter moduleis removed from the filter housing 2. In the installed state, asillustrated in FIG. 2, the valve tappet 96 contacts the distributor head120, so that the valve opening 95 is opened.

The adapter valve 100 (see FIG. 3) in the lower adapter 26 is installedcorrespondingly, with the valve plate 104 likewise projecting into thefiltrate channel 18. The valve plate 104 is similarly arranged so thatit closes the valve opening 105 when the filter module is removed fromthe filter housing 2. The valves 90, 100, 40, and 48 thus enabledrip-free removal of the filter module.

To enable the installation of the filter module in a conventional filterhousing, an installation set is provided, which is described in moredetail in connection with FIGS. 2 and 3.

In FIG. 2, the upper components of the installation set are shown. Thecover plate consists of an annular head plate 110, whose outer contours,as shown in FIG. 1, are adapted to the inner contours of the housingcover wall 8 and the housing shell 10. The lower side 112 of the headplate 110 forms a contact surface for the envelope 30. Here, it isimportant that only a small distance is maintained to the housing shell10 so that during the filtration the noncompression-proof envelope 30cannot bulge out so far that it is damaged. Furthermore, the head plate110 has a ring receiver 116 for the upper retaining ring 32.

Furthermore, a distributor head 120 is inserted in the center in thehead plate 110. This distributor head extends upwards through thehousing connection 6. In the distributor head 120, as can be seen inFIG. 2, there is a ventilation channel 128 a, 128 b, which connects tothe valve opening 36 of the valve 40 over the annular chamber 126.Therefore, the air escaping from the nonfiltrate chamber can bedischarged through the outlet 130 at the upper end of the distributorhead 120. In the region of the annular chamber 126, a stop 124 is formedon the distributor head 120 for the valve tappet 44, which holds thevalve 40 in the open position in the installed state. The distributorhead 120 further has an annular flange 122 for receiving the upperadapter 24.

In the center in the distributor head 120, there is a ventilationchannel 132 with the channel branches 134 a and b, which connect to thefiltrate channel 18.

Furthermore, located in the distributor head 120 is a control channel136, which connects over the channel branches 138 and 140 to theintermediate spaces between the head plate 110 and the housing upperpart 4 and thus also to the intermediate space between the envelope 30and the housing shell 10. If the envelope 30 is damaged, the nonfiltratematerial would flow outwards through the channel branches 138, 140 andthe control channel 136 and thus could be detected.

However, the control channel 136 can also be attached to a pressuredevice. If the pressure device is an overpressure device, e.g.,compressed air can be blown into the channels 138, 140 so that theenvelope is pressed against the filter cells 22. This enables residualfiltration to be performed at the end of filtration.

The control channel 136 can also be attached to a low-pressure device,so that the filling process at the beginning of filtration can besupported by suction in the envelope 30 up to the attachment to thehousing wall.

As can be seen in FIG. 3, an annular base plate 60 is arranged betweenthe base plate 12 and the filter module. The radial dimension of thisbase plate essentially corresponds to the inner dimension of the housingshell 10. The base plate 60 has a surface 66, which rises towards theoutside in the radial direction and which forms a contact surface forthe envelope 30. Because the envelope 30 is not pressure-sealed, it isimportant that the base plate 60 extends as close as possible to theinner side of the housing shell 10, so that the envelope 30 is notdamaged in the transition region between the base plate and the housingshell by the inner pressure in the filter module.

The base plate 60 has a nonfiltrate channel 62 which connects thenonfiltrate supply 14 of the base wall 12 to the valve opening 38 of thevalve 48. The annular base plate 60 has a ring receiver for receivingthe retaining ring 34 and carries a receiver bushing 70 arranged in thecenter for receiving the lower adapter 26. The receiver bushing 70 has alower bushing section 74 and an upper bushing section 72 that widensoutwards in the radial direction for receiving the adapter 26. An innershoulder 76 and an outer shoulder 78 are formed by the radial offset.With the outer shoulder 78, the receiver bushing 70 contacts acorresponding surface of the base plate 60. The inner shoulder 76 isused to support the valve ring 102 of the adapter valve 100. Aprojection 80 as a stop for the valve tappet 52 of the inlet valve 48 isarranged radially outwards on the upper bushing section 72. The positionof the projection 80 is selected so that the valve tappet 52 presses thevalve cover 50 upwards, so that the valve opening 38 is opened.

In FIG. 4, another embodiment is shown which concerns the installationof two schematically illustrated filter modules. In order to be able toconnect the two filter modules to each other, an intermediate plate 150is provided with end surfaces 154, 156 as contact surfaces for theenvelopes 30, 30′. The annular intermediate plate 150 receives the lowerretaining ring 34′ of the upper filter module and the upper retainingring 32 of the lower filter module. The intermediate plate 150 extendswith its outer peripheral surface 152 into the vicinity of the innersurface of the housing shell 10. Furthermore, the intermediate plate 150has a ring element 160 for receiving the adapter 26′ and 24. The valves40 and 48′ are connected to each other over a connection channel 158. Aprojection 162 of the ring element 160 projects into this connectionchannel and this projection acts as a stop for the valve tappet 52′ and44.

1. A module for filtering media comprising: an axially extending centralchannel; a first hollow adapter having an interior through which thecentral channel extends and an exterior; a second hollow adapter havingan interior through which the central channel extends and an exterior;one or more filter cells positioned between the first and secondadapters and around the central channel, wherein each filter cellincludes first and second filter layers and wherein each filter layerhas an inner surface and an outer surface, the first and second layersdefining a passage that fluidly communicates between the inner surfacesof the filter layers and the central channel; and an enclosure includinga first retainer ring mounted around the exterior of the first adapter,a second retainer ring mounted around the exterior of the secondadapter, and an envelope extending around the one or more filter cellsand including a first region sealed to the first retainer ring, a secondregion sealed to the second retainer ring, and an exterior, wherein theenclosure further has an opening that fluidly communicates between theexterior of the enclosure and the second surfaces of the filter layersof the one or more filter cells.
 2. The filter module of claim 1 whereinthe one or more filter cells comprise a plurality of filter cellsstacked on one another between the first and second adapters and aroundthe central channel.
 3. The module of claim 1 wherein the envelopecomprises a flexible and/or elastic material.
 4. The module of claim 1wherein the two adapters are identical.
 5. The module of claim 1 whereinthe opening is positioned in one of the retainer rings.
 6. The module ofclaim 1 wherein the opening comprises a first opening and the enclosurefurther has a second opening that fluidly communicates between theexterior of the enclosure and the second surfaces of the filter layersof the one or more filter cells, the first opening being positioned inthe first retainer ring and the second opening being positioned in thesecond retainer ring.
 7. The module of claim 1 wherein one of theadapters includes a valve arranged to close the central channel.
 8. Themodule of claim 1 wherein the adapter valve is a plate valve.
 9. Afilter device comprising a housing and a filter module of claim 1disposed in the housing, the housing having a media inlet fluidlycommunicating with one of the central channel and the opening in theenclosure and a filtrate outlet fluidly communicating with the other ofthe central channel and the opening in the enclosure.
 10. The filterdevice of claim 9 wherein the housing has an interior and wherein theexterior of the envelope contacts the interior of the housing.